Spark plug cooling device



I May 18, 1937. L J. MCKQNAE 2,080,495

SPARK PLUG COOLING DEVICE e0 (IMC/fan@ May 18,l

1937. L. J. McKoNE 2,080,495

SPARK PLUG COOLING DEVICE Filed June 22, 1935 2 Sheets-Sheet 2 Patented May I8, 1937 UNITED STATES SPARK PLUG COOLING DEVICE Leo J. McKone, Chicago, Ill., asslgnor of one-half to Dean D. Francis, Cleveland, Ohio, and oneeighth to Kenneth Application June 22,

15 Claims.

'Ihis invention relates to a device for cooling spark plugs in use on internal combustion engines and includes a method of cooling said plugs.

More specifically this inventory relates to a device for enclosing the exposed portions of spark plugs together with means for flowing air through the device by induced draft caused by the operation of the motor.

In my copending application entitled: Spark plug", Serial No. 5192 filed February 6, 1935, I have described and claimed a spark plug provided with spaced radiating fins for dissipating heat from the plug. I have now found that a superior cooling of spark plugs can be effected by surrounding these uns with a container to enclose the exposed part of the spark plug and drawing air through the container to absorb heat from the plug. The hot air can then be used for combustion purposes within the motor. While my cooling device is particularly adapted for use with spark plugs having radiating ilns formed thereon it should be understood that it can also be used with ordinary types of spark plugs.

In accordancewith my invention I provide a small metallic container around each spark plug. The container is open at the bottom and is provided with an opening near the top thereof connected to a header duct. The header duct is connected with the air intake of the motor or with other means for drawing air therethrough. In this manner a draft of air is created around each of the spark plugs and they are maintained in a cool condition. Means may be provided in the header duct to control the amount of air flowing therethrough in the event that it is desired to allow the spark plug to become heated to a desired temperature before the cooling draft is created. This regulating means may conveniently be controlled by the automatic choke device commonly used in automotive vehicles.

It is therefore an object of this invention to provide a device for circulating air around the ex-y posed parts of a spark plug to cool the plug.

A further object of this invention is to effect a cooling of spark plugs in use on internal combustion engines by creatinga forced draft around each plug. y

Another object of this invention is to shield the spark plugs individually in metallic containers to prevent short circuiting thereof and to create a draft of air through said containers for cooling the plug.

A specific object of this invention is to form individual metallic containers for spark plugs and to connect said containers with the air intake of E. Lymn, Chicago, Ill.

1935, Serial No. 27,998

(Cl. 12S-169) an internal combustion engine for circulating air through the container to cool the plug and heat the air before feeding into the carburetor.

Other and further objects of this invention will be apparent from the following detailed descrip- 'tion of the annexed sheets of drawings which disclose preferred embodiments of the invention.

On the drawings:

Figure 1 is a side elevational view of an automobile engine provided with a down-draft carburetor and an air cleaner illustrating the manner in which the spark plug cooling device of this invention may be mounted to supply heated air to the carburetor.

Figure 2 is a diagrammatic fragmentary view illustrating the manner in which the cooling device of this Vinvention may be equipped with a Venturi apparatus located in the slip stream of an airplane for effecting circulation of air around the spark plugs of an airplane engine.

Figure 3 is an enlarged cross-sectional view. with parts in elevation, taken substantially along the line IH--III of Figure l.

Figure 4 is an enlarged cross-sectional view, with parts in elevation, taken substantially along the line IV-IV of Figure l.

Figure 5 is a cross-sectional view taken substantially along'the line V-V of Figure 4.

Figure 6 is an enlarged cross-sectional detail view showing a preferred manner of mounting the contact points in a spark plug used in this invention.

Figure 7 is a plan view of a metal washer adapted to effect contact between the spark plug and the automobile engine.

Figure 8 is a cross sectional view taken substantially along the line VIII-VIII oi Figure 7 showing in dotted lines the manner in which the extending ears of the washer are bent upward when in use.

As shown on the drawings:

In Figure l the reference numeral I0 indicates generally an automobile engine having a head Il with spark plugs I2 extending therefrom. The engine l0 is provided with the customary exhaust manifold i3. The manifold i 3 carries a thermostat device Il operatively connected to a downdraft carburetor i5 to automatically control the choking of the gasoline feed into the engine. The down-draft carburetor I5 is connected with an intake manifold I3a through a heat exchanger i6 of the customary type for heating the intake fuel and air mixture by the exhaust gases from the motor before delivering this charge to the intake manifold Na. Air for the carburetor i5 passes through an air cleaner I1 of the customary type mounted on top of the engine I6.

The device of this invention consists of open bottomed containers or shrouds I 6 surrounding each spark plug I2. These containers I6 communicate through tubes I3 at the top thereof with a header duct 20 which is closed at one end 2i thereof and which is connected through a tube 22 to the inlet end 23 of the air cleaner I1. 'Ihus when air is drawn through the air cleaner I1 on the intake strokes of the motor I the header duct 20 is subjected to suction thereby drawing air through the containers I8 and tubes I9. In this manner the spark plugs I2 are cooled by the circulation of air therearound and air fed to the carburetor is heated. The amount of air flowing through the header duct 20 `may be automatically controlled by the thermostatic device I4 which controls the automatic choke in the carburetor I5 by providing a damper 24 (best shown in Figure 4) in the duct 20 near the front end thereof. An arm 25 extends through the duct for controlling the damper 24. This arm 25 is connected through a rod 26 (Figure l) to an arm 21 operated by the thermostatic device I4 which arm 21 also controls the automatic choke of the carburetor I5.

In Figure 2 I have illustrated diagrammatically the manner in which the cooling device of this invention may be applied to airplanes. In Figure 2 the reference numeral 30 indicates diagrammatically the fuselage of an airplane and the reference numeral 3i indicates the airplane engine having a spark plug I2 extending therefrom covered by a container I6 which is connected with the header duct 25 in the identical manner which is illustrated in Figure 1.

A Venturi device 32 is mounted in the slip stream or propeller wash adjacent the fuselage and may be secured to the fuselage by a bracket 33. The Venturi device 32 consists of a funnel shaped member 34 having an annular shroud 35 disposed around the enlarged end thereof as shown. As air flows through the shroud 35 as indicated by the arrows a suction eil'ect is created within the funnel shaped member 34 to draw air therefrom. As a result, air is drawn through the container I8 and header duct 2B to cool the spark plug I2. The amount of air flowing through the container I 6 may be controlled by a damper 35 located at the small end of the Venturi device 32. This damper has a control arm 31 extending therefrom and may be set to the desired position by a Bowden wire 36 leading to the dash board in the pilots compartment of the airplane. A manual setting of the Bowden wire makes possible the regulation of the amount of air flowing through the container I6. It should be understood that the Venturi device 32 may be mounted any place in the slip stream or propeller wash of an airplane.

As best shown in Figures 4, 5, and 6, the preferred form oi spark plug I2 used in this invention comprises a porcelain core 40 having an enlarged portion 4I near the bottom thereof and a tapered end 42. A contact point 43 of tungsten or other suitable metal extends from the bottom of the tapered end 42 and a binding post 44 connected with the contact point 43 extends from the top of the porcelain core 40.

A metal boss 45 is slipped over the porcelain core 40 until the bottom thereof abuts the enlarged portion 4I of the core. The boss 45 is threaded into a shell 46 having an enlarged opening 41 therein for receiving the enlarged 'ing 45 for receiving the end 42 of the core.

commeV portion 4I of the core 4l and the end of the boss 45. The bottom portion of the shell 46 tapers inward as at 46 to define a restricted open- The end of the shell 46 is threaded as shown at 50.

A shoulder 5| is formed between the openings 41 and 49 of the shell 46 and a packing gasket 52 is seated on this shoulder. 'Ihus when the boss 45 is threaded into the shell 45 the enlarged portion 4I of the core 46 is compressed against the gasket 52 for sealing the space 49 from the space 41.

The threaded end of the shell 45 carries a depending lug 53 at the bottom thereof separated from the portion 50 by a groove 54. The lug 53 carries the other contact point 55 of the spark plug. This construction maintains the heat generated by the spark passing between the contact points localized in the combustion chamber. The groove 54 dams oif the travel oi heat from the contact point 55 into the shell 48 and thereby aids in maintaining the spark plug in a cool condition. The size of the groove 54 may be varied to suit operating conditions of diierent internal combustion engines and thus make it possible to localize the heat generated by the spark and prevent the same from traveling into the upper portions of the spark plug.

The heat may be further localized within the combustion chamber by the use oi' an asbestos washer 55 (Figures 3 and 4) in place of the usual copper gasket. This asbestos washer 55 is a nonconductor both for heat and for electricity. Therefore in order to insure a good electrical contact between the shell 46 carrying the contact point 55 of the plug and the motor a metallic washer 51 shown in Figures 7 and 8 is used. This washer 51 is provided with laterally extending ears 56 a'nd 53 which, when depressed into the spark plug well o! the engine head II as shown in Figure 3 are bent upwardly and because of the inherent springiness of the metal forming the washer 51 a good electrical contact is maintained between the head II and the shell 46 of the plug. It has been found that the threaded portion 55 of the plug becomes fouled with carbon during use and cannot be relied upon for good contact between the engine head `II and the plug. I have therefore found it desirable to use a type of washer such as shown in Figures 7 and 8 to maintain a good electrical contact. The use of the asbestos washer 56 and the groove construction for supporting the contact 55 very satisfactorily localizes the heat generated by the spark in the combustion chamber.

As best shown in Figure 5, the shell 46 of the plug is provided with a plurality of radially extending fins 46a in spaced relation from each other. These ilns are formed integral with the shell 45 and receive therearound the container or shroud I6. This container I6 as best shown in Figures 3 to 5 comprises a cylindrical metal tube 66 which snugly iits over the ns 46a. 'Ihe tube 66 is provided intermediate its ends with an inturned bead 6I adapted to snap in a corresponding groove formed in the ilns 46a for maintaining the bottom of the container in spaced relation from the washer 51 so that air may enter into the tube at this pointgaiong the passageways 62 formed between the radiating fins 46a.

A circular opening 63 is formed in the side wall of the tube 65 near the top thereof for receiving the tube I9 which is welded, brazed or soldered in the opening 63 at one end and communicates with the header duct 26 at the other end. The tube i9 is also welded, brazed or soldered to the header duct as shown.

'Ihe top of the cylindrical tube 60 is closed with a cover 84 which fits thereover as shown.

As shown in `igure 4 the cover 6l is provided with an enlarged opening 65 in the center thereof through which the binding post 44 of the plug may extend. An insulation washerv 68 of asbestos, rubber or other material is disposed between the top of the core 40 of the plug and the cover 64 to maintain the cover in insulated relation from the cover. Binding post nuts. are threaded onto the binding post u and are in spaced relation from the cover 6I as shown. These binding post nuts are also spaced from the cover. 64. 'I'he cover '6l may be held in position on the tube 60 by a peripheral flange 64a integral with the cover. The flange 64a frictionally grips the top of the tube 60.

It should be understood/,that the container I8 can be formed in one piece by a drawing operation but it is preferredvv to forin the container with a removable cover as shown for inspection of the plug without removing the container.

The spark plugs may readily be removed from the engine head Il by disengaging the header duct 20 from the pipe 22 and withdrawing the containers I8 from the plugs. A gripping tool adapted toengage the radiating fins 46a of the plug is then disposed around the plug and the same is readily unseated from the head il by rotation of the shell I6 to unscrew the plug.

From the above description it should be evident that I have provided means for localizing the heat generated by a spark plug in the combustion chamber and means to cool the exposed parts of the plug by induced draft caused by operation of the motor in which the plugs are seated. 'Ihese induced drafts are created without loss of operating power of the motor. The cooling device of this invention is simple in construction, can be manufactured at very low cost, is entirely automatic in operation and greatly improves the operating eillciency. of internal combustion engines. y

I am aware that many" changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting Vthe Vpatent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

l. A cooling device for spark plugs comprising an individual container adapted to-be snapped around the exposed part of a single spark plug and carried by said plug and means for creating exposed parts of said spark plugs, a header duct communicating with each of said containers near the top thereof, means communicating with one end of said header duct for withdrawing air therefrom to draw fresh air into said container around said spark plug and means for controlling the amount of air withdrawn through said header duct..

4. In combination with an internal combustion engine having a plurality of spark plugs extending therefrom, and an air intake to said engine, metallic containers disposed over each of said spark plugs, a header duct communicating with each of said containers near the top thereof, means for connecting one end of said header duct with the air intake to draw air through said duct from said containers for cooling the spark plugs and for heating the air fed to the engine, and means for controlling the' amount of air drawn through said header duct.

5. In combination with an internal combustion engine having a plurality of spark plugs extending therefrom, and an air intake to said engine, a metallic container disposed over each of said spark plugs, a header duct communicating with said containers and with said air intake, and ay damper in said header duct for controlling the amount of air flowing through said duct.

6. In combination with an internal combustion engine having a plurality of spark plugs extending therefrom, a container disposed over each of said spark plugs, a Venturi device communicating with said containers to draw air therethrough for cooling said spark plugs and manually operative means for controlling the amount of air drawn through said containers.

7. In combination with an internal combustion engine having a plurality of spark plugs extending therefrom, a metal container disposed over each of said spark plugs, and a Venturi device communicating with the interior of each of said containers for drawing air therethrough to cool the spark plugs.

8. In combination with a spark plug having a shell portion provided with a plurality of radially extending fins, a metal tube disposed around said fins, said tube having an open bottom in spaced relation from the bottom of said fins, means for closing the top of said tube, and means for drawing air thru said tube tocool the spark plug.

9. In combination with a spark plug having a shell formed with a plurality of radially extending fins and means for localizing the heat generated by the spark in the combustion chamber of an automotive engine, a container adapted to be snapped over said fins in spaced relation from the bottom thereof and means for circulating air through said container along the passageways formed between the fins for cooling the spark plug.

10. In combination with a spark plug having a shell formed with a plurality of radially extending ns and carrying a spark electrode on a grooved lug therebelow for localizing the heat of the spark within the combustion chamber of the engine, a metallic container adapted to be snapped around said fins in spaced relation from the bottom thereof to define together with the fins a plurality of passageways and means for withdrawing air from the top of said container to flow fresh air along said passageways for cooling said plug.

11. In combination with a spark plug having a shell portion provided with a plurality of radially extending fins and a threaded portion on said shell portion for threading the plug into an internal combustion engine, said threaded portion having a lug extending therebelow and separated therefrom by a groove, a contact rod secured in said lug, a container adapted to be snapped around said radiating iins in spaced relation from the bottom thereof to denne together with the fins a plurality of passageways for air around the spark plug and means communicating with the top of said container for withdrawing air therefrom to thereby draw fresh sir through said passageways for cooling the plugs.

v12. In combination with an internal combustion engine, a spark plug threaded therein, a lug extending from the bottom of said spark plug having a groove out therein for damming otr the` lug from the plug, a contact rod extending from said lug below said groove, a heat insulating washer around the spark plug above the threaded portion thereof. a metallic washer around said plug pressed tightly thereagainst above said heat insulating washer, said metallic washer having laterally extending portions for contacting the engine to effect a good electrical contact between said contact rod and engine, a container disposed over said spark plug in spaced relation from the metallic washer and means for flowing ail thrczug h said container for cooling said spark D B18.

13. In a spark plug assembly including a spark plug and an internal combustion engine having a depressed well with a threaded opening at the bottom thereof communicating with the combustion chamber of the engine for receiving the spark plugin threaded relation in said opening, an asbestos washer around said spark plug above said opening and aspx-ing metal washer ntted snugly around said spark plug above the asbestos washer, said metal washer having extending ears adapted to be depressed into the well oi' the engine to llrmly contact the walls thereof.

1 43. In combination with an internal combustion engine having a plurality of spark plugs extending therefrom, individual containers covering the exposed part of each spark plug and carried by the spark plugs and means for positively impelling air through said containers around said spark plugs.

'15. A cooling device for spark plugs comprising'a container adapted to be disposed around substantially the entire exposed part of a spark plug and carried by said plug, and means for positively impelling air through said container around said spark plug.

` LEO J. MCKONE. 

